I just went thru this. I suggest you make sure its a hair over 16" because if its any under its a large fine and jail time . Yes it would have to be permanently attached pinned and I suggest welded . Now the question I have for u is why go thru all this when it will still
be 16" long ? Honestly its really pointless to do that , if u want a 10" barrel go thru all the BS pay the $200 wait the 6 months and get what u want
I was planning on it, can't be too safe.
As a pistol 10" was good, but as a rifle 16" doesn't bother me at all. Plus If I had 200$ to dump into a tax I'd pay it to a legit suppressor and weld that to it.
Anyway, I just shot them an email to see what they say.